4 files changed, 21 insertions, 6 deletions
diff --git a/tests/ui/box_default.fixed b/tests/ui/box_default.fixed
index e6331290420..fb066d8982e 100644
--- a/tests/ui/box_default.fixed
+++ b/tests/ui/box_default.fixed
@@ -1,6 +1,6 @@
 //@run-rustfix
 #![warn(clippy::box_default)]
-#![allow(clippy::default_constructed_unit_structs)]
+#![allow(unused, clippy::default_constructed_unit_structs)]
 
 #[derive(Default)]
 struct ImplementsDefault;
@@ -35,6 +35,13 @@ fn main() {
     let _more = ret_ty_fn();
     call_ty_fn(Box::default());
     issue_10381();
+
+    // `Box::<Option<_>>::default()` would be valid here, but not `Box::default()` or
+    // `Box::<Option<[closure@...]>::default()`
+    //
+    // Would have a suggestion after https://github.com/rust-lang/rust/blob/fdd030127cc68afec44a8d3f6341525dd34e50ae/compiler/rustc_middle/src/ty/diagnostics.rs#L554-L563
+    let mut unnameable = Box::new(Option::default());
+    let _ = unnameable.insert(|| {});
 }
 
 fn ret_ty_fn() -> Box<bool> {
diff --git a/tests/ui/box_default.rs b/tests/ui/box_default.rs
index 34a05a29c5a..2882170492c 100644
--- a/tests/ui/box_default.rs
+++ b/tests/ui/box_default.rs
@@ -1,6 +1,6 @@
 //@run-rustfix
 #![warn(clippy::box_default)]
-#![allow(clippy::default_constructed_unit_structs)]
+#![allow(unused, clippy::default_constructed_unit_structs)]
 
 #[derive(Default)]
 struct ImplementsDefault;
@@ -35,6 +35,13 @@ fn main() {
     let _more = ret_ty_fn();
     call_ty_fn(Box::new(u8::default()));
     issue_10381();
+
+    // `Box::<Option<_>>::default()` would be valid here, but not `Box::default()` or
+    // `Box::<Option<[closure@...]>::default()`
+    //
+    // Would have a suggestion after https://github.com/rust-lang/rust/blob/fdd030127cc68afec44a8d3f6341525dd34e50ae/compiler/rustc_middle/src/ty/diagnostics.rs#L554-L563
+    let mut unnameable = Box::new(Option::default());
+    let _ = unnameable.insert(|| {});
 }
 
 fn ret_ty_fn() -> Box<bool> {
diff --git a/tests/ui/box_default.stderr b/tests/ui/box_default.stderr
index c9834863601..13dfc5ae48a 100644
--- a/tests/ui/box_default.stderr
+++ b/tests/ui/box_default.stderr
@@ -73,25 +73,25 @@ LL |     call_ty_fn(Box::new(u8::default()));
    |                ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::default()`
 
 error: `Box::new(_)` of default value
-  --> $DIR/box_default.rs:41:5
+  --> $DIR/box_default.rs:48:5
    |
 LL |     Box::new(bool::default())
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<bool>::default()`
 
 error: `Box::new(_)` of default value
-  --> $DIR/box_default.rs:58:28
+  --> $DIR/box_default.rs:65:28
    |
 LL |     let _: Box<dyn Read> = Box::new(ImplementsDefault::default());
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<ImplementsDefault>::default()`
 
 error: `Box::new(_)` of default value
-  --> $DIR/box_default.rs:67:17
+  --> $DIR/box_default.rs:74:17
    |
 LL |         let _ = Box::new(WeirdPathed::default());
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<WeirdPathed>::default()`
 
 error: `Box::new(_)` of default value
-  --> $DIR/box_default.rs:79:18
+  --> $DIR/box_default.rs:86:18
    |
 LL |             Some(Box::new(Foo::default()))
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<Foo>::default()`
diff --git a/tests/ui/let_underscore_untyped.rs b/tests/ui/let_underscore_untyped.rs
index 05ecd9b281a..2c313ff35d5 100644
--- a/tests/ui/let_underscore_untyped.rs
+++ b/tests/ui/let_underscore_untyped.rs
@@ -54,6 +54,7 @@ fn main() {
     let _ = e();
     let _ = f();
     let _ = g();
+    let closure = || {};
 
     _ = a();
     _ = b(1);